Strengthening of I-Section Steel Beams by Prestressing Strands

2020 ◽  
Vol 857 ◽  
pp. 169-176
Author(s):  
Kamal Sh. Mahmoud ◽  
Mohammed M. Rasheed ◽  
Saad Kh. Mohaisen
Keyword(s):  
Applied Load ◽  
Reference Beam ◽  
Experimental Tests ◽  
The Other ◽  
Steel Beams ◽  
Steel Beam ◽  
Maximum Deflection ◽  
Sectional Area ◽  
Simply Supported ◽  
Prestressing Strand

Six I-section steel beams had been fabricated and tested to understand the influence of prestressing strand on the load deflection behavior of steel beam. All tested beams are simply supported having the same gross sectional area with clear span (2850) mm, five beams strengthened by two low relaxation seven wire strands, while sixth beam is the reference one. The strengthening beams were subjected jacking stress equal to (1120MPa) and subdivided according to prestressing strand positions (eccentricity). From the experimental tests, it can be noted that, the load deflection curves for strengthened beams are stiffer as compared with reference beam and the percentage of ductility for strengthened beams were decreased when the eccentricity positions change form (0 to 96)mm respectively, on the other hand, the percentage of increasing in maximum applied load for strengthened beams were increased with increasing of strands eccentricity and the maximum applied load reaches to 61.74% as compared with reference, also, the percentage increasing in maximum deflection at middle span for strengthened beams decreases with increasing of strands eccentricity and the minimum percentage of decreasing at middle span of strengthened specimens reaches to 36.31% as compared with the reference beam.

scholarly journals The Behavior of a Strengthened Steel Beam Section Under Eccentric Loadings

2021 ◽  
Vol 318 ◽  
pp. 03007
Author(s):  
Mohammed M. Rasheed ◽  
Kamal Sh. Mahmoud ◽  
Saad Khalaf Mohaisen ◽  
Mohammed Z. Yousif
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
The Other ◽  
Steel Beams ◽  
Steel Beam ◽  
Ultimate Load Capacity ◽  
Cross Sectional ◽  
External Prestressing ◽  
Beam Section ◽  
Prestressing Strand

Thirteen simply supported steel samples have been tested to explain the effects of strengthening steel beams using an external prestressing strand. The samples have the same cross-sectional dimensions and overall length. One steel beam without strengthening was taken as a reference, while the other twelve of them had been strengthening by two external strands at various eccentricity locations and jacking stresses. The strengthening by external prestressing strands is sub-divided into two series according to jacking stress. Each series consists of six steel samples divided according to the eccentricity location of prestressing strand. During tests, it was found that the Load deflection response for the strengthened samples is stiffer as compared with the reference. The increasing percentage in ultimate load capacity was increased to 0.347, 2.758, 3.921, 8.898, 9.326, and 10.256% for beams under jacking stress of 1120 MPa, while increasing percentage in ultimate load capacity were increased to 0.17, 26, 33, 48.5, 13.7, and 69.56% for beams under jacking stress of 815 MPa. On the other hand, the maximum percentages of deflection were decreased to 4.88, 2.44, 20.62, 15, and 9.7% when the jacking stress increase from 815 to 1120 MPa and the ratio of the quarter to mid-span deflection (δ quarter / δ mid) is about 0.528 and 0.497 when jacking stress is 1120 and 815 MPa respectively. So, the increase in jacking stresses from 815 to 1120 MPa will not be preferable because it has a little increasing percentage in stiffening and behaviors compared with other tested beams at the same condition.

scholarly journals Effect of Prestress Force on Natural Bending Frequency of External Prestressed Steel Beams

2018 ◽  
Vol 12 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Tang Bai-jian ◽  
Wang Fei ◽  
Chen Song
Keyword(s):  
Natural Frequencies ◽  
Cross Sectional Area ◽  
Steel Beams ◽  
Steel Beam ◽  
Sectional Area ◽  
View Point ◽  
The Finite Element Method ◽  
Cross Sectional ◽  
Simply Supported ◽  
Odd Order

Introduction: Natural bending frequencies of externally prestressed steel beam have certain sensitivity to prestress force, so they can be used to find the magnitude of prestress force. Methods: To answer the question if the existence of externally prestressed tendons increases or decreases the natural bending frequencies of a simply supported steel beam, the calculating formula for natural frequencies is deduced by using the energy method from the view point of prestress mechanism and further verified by the finite element method. Using this formula of universal property, the influence of prestress force, eccentricity and cross-sectional area of tendons on natural bending frequencies of prestressed steel beam is clearly revealed. Results and Conclusion: For external prestressed steel beams with straight tendons, their natural frequencies increase with the eccentricity and cross-sectional area of the prestressed tendon, and the eccentricity has a much larger effect on natural frequencies than the cross-sectional area does. The prestress force has no influence on the oven-order frequencies but decreases the odd-order frequencies. With the increasing order number, the prestress effect is much weaker than the effects caused by the eccentricity and cross-sectional area of the tendon.

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

A Comparison Study between Asymmetrical Castellated Steel Beams Encased by Reactive Powder Concrete with Laced Reinforcement

2021 ◽  
Vol 895 ◽  
pp. 77-87
Author(s):  
Hussamalden Alqahar Ammar ◽  
Ahmad Jabbar Hussain Alshimmeri
Keyword(s):  
Experimental Tests ◽  
Longitudinal Axis ◽  
Reactive Powder Concrete ◽  
Steel Beams ◽  
Steel Beam ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Concentrated Loads ◽  
Load Carrying ◽  
Reactive Powder

The main objectives of this study are to study the enhancement of the load-carrying capacity of Asymmetrical castellated beams with encasement the beams by Reactive Powder Concrete (RPC) and lacing reinforcement, the effect of the gap between top and bottom parts of Asymmetrical castellated steel beam at web post, and serviceability of the confined Asymmetrical castellated steel. This study presents two concentrated loads test results for four specimens Asymmetrical castellated beams section encasement by Reactive powder concrete (RPC) with laced reinforcement. The encasement of the Asymmetrical castellated steel beam consists of, flanges unstiffened element height was filled with RPC for each side and laced reinforced which are used inclined continuous reinforcement of two layers on each side of the Asymmetrical castellated steel beam web. The inclination angle of lacing reinforcement concerning the longitudinal axis is 45. Four specimens with four different configurations will be prepared and tested under two concentrated loads at the mid-third of the beam span. The tested specimen's properties are the First model; unconfined, Asymmetrical castellated steel beam (Reference), while the second, third, and fourth models consist of Asymmetrical Castellated steel beam (web and flange) confined with (RPC) with 19.1, 38.2, and 57.3 mm gap, respectively, between the two beams sections (the upper and lower one). The results of the experimental tests show that the use of RPC enhanced the properties of the castellated beams in all selected conditions despite creating a gap between the castellated beams.

Deflection Change Analysis of Bending Steel Beam under High Temperature and Uniform Loads

2014 ◽  
Vol 1065-1069 ◽  
pp. 1319-1322
Author(s):  
Yu Lai Han ◽  
Xiao Le Zhang ◽  
De Wei Jiao ◽  
Zuo Hua Cai ◽  
Yan Li
Keyword(s):  
Mechanical Properties ◽  
Building Materials ◽  
Steel Structure ◽  
The Other ◽  
Steel Beams ◽  
Steel Beam ◽  
Change Analysis ◽  
Fire Temperature ◽  
Materials Properties ◽  
Structure Building

In case a fire occurs in a steel structure building, materials properties and mechanical properties have undergone great changes, especially bending beam, its force complex than other members, charged with an important role in the structure, when the fire broke out the other members also prone to failure. This article refer to the document [1], the deflection change of bending steel beams subjected to fire are studied, analyzed its variation trend with the fire temperature, the accurate judgement of the stress state on the fire burning at different time can make the stress analysis more accurate and reasonable.

scholarly journals Dynamic Response of Composite Plate Subjected to Sudden Heat Flux

2017 ◽  
Vol 11 (12) ◽  
pp. 36 ◽  
Author(s):  
Salih Akour
Keyword(s):  
Heat Flux ◽  
Composite Plate ◽  
Epoxy Composite ◽  
Plate Thickness ◽  
Composite Plates ◽  
The Other ◽  
Stacking Sequence ◽  
Maximum Deflection ◽  
Element Analysis ◽  
Simply Supported

Composite plates’ subjected to sudden surface heating is investigated. Simply supported boundary conditions along the four sides of the plat are considered. The effect of plate thickness and stacking sequence on the maximum deflection that is induced by the thermal heat flux for a graphite-epoxy composite plate is studied using finite element analysis. Symmetric angle ply laminates plate shows least deformation compared the other stacks of the same thickness.

scholarly journals STUDYING THE BEHAVIOUR OF LIGHTWEIGHT DEEP BEAMS WITH OPENINGS

2020 ◽  
Vol 6 (12) ◽  
pp. 89-100
Author(s):  
Oday Adnan Abdulrazzaq ◽  
Ashraf Mahammed Khadhim
Keyword(s):  
Ultimate Load ◽  
Lightweight Concrete ◽  
Experimental Tests ◽  
Steel Reinforcement ◽  
Deep Beam ◽  
Maximum Deflection ◽  
Deep Beams ◽  
Simply Supported ◽  
Shear Span ◽  
Shape And Size

In this study experimental tests were conducted to investigate the behavior of reinforcedconcrete deep beam with openings using lightweight concrete. The experimental programinvolved of testing thirteen simply supported deep beam specimens which tested under statictwo-point loads. Light expanding clay aggregate (LECA) was used to produce lightweightconcrete. Test variables were the shape and size of openings, reinforcement around theopenings, position of the openings and shear span to depth ratio. It was found that thebehavior of deep beams which made of lightweight concrete is similar to that made of normalconcrete. It was concluded that the ultimate load and the measured maximum deflection inbeams that have circular openings are larger compared to that have rectangular openings. Atthe same time, the ultimate load decreased and the measured values of maximum deflectionincreased with increasing the size of the openings in deep beams. Also, it was found thatproviding steel reinforcement around the openings caused an increasing in the load capacityof the tested beams. Decreasing the shear span ratio from 0.5 to 0.4 caused an increasing inthe ultimate load and the measured maximum deflection.

Assessment Model for the Safety and Serviceability of Steel Beams Using Terrestrial LiDAR

2006 ◽  
Vol 321-323 ◽  
pp. 248-253 ◽  
Author(s):  
Hyo Seon Park ◽  
H.M. Lee ◽  
Y.H. Kwon ◽  
J.H. Seo ◽  
Hong C. Rhim
Keyword(s):  
Stress Level ◽  
Maximum Stress ◽  
Practical Method ◽  
Assessment Model ◽  
Steel Beams ◽  
Steel Beam ◽  
Building Structures ◽  
Maximum Deflection ◽  
Lidar System ◽  
Terrestrial Lidar

Structural monitoring is concerned with the safety and serviceability of the users of structures, especially for the case of building structures and infrastructures. When considering the safety of a structure, the maximum stress in a member due to live load, earthquake, wind, or other unexpected loadings must be checked not to exceed the stress specified in a code. Although the steel will not fail at yield, excessively large deflections will deteriorate the serviceability of a structure. Therefore, to guarantee the safety and serviceability of steel beams, the maximum stress and deflection in a steel beam must be monitored. However, no practical method has been reported to monitor both the maximum stress and deflection. In this paper, assessment model for both safety and serviceability of a steel beam is proposed. The model was tested in an experiment by comparing stress level estimated by LiDAR system and stress level directly measured from electrical or fiber optic sensors. The maximum deflection measured from LiDAR system is also compared with the maximum deflection directly measured from LVDTs. In addition to displacement measurement, the proposed system can provide information on deformed shapes of steel beams.

Possibility of Application of the Simulation Based Reliability Assessment Method in Modeling of Structures

2013 ◽  
Vol 486 ◽  
pp. 129-134
Author(s):  
Petr Kesl ◽  
František Plánička
Keyword(s):  
Reliability Assessment ◽  
Random Variable ◽  
Assessment Method ◽  
Composite Model ◽  
Steel Beam ◽  
Sectional Area ◽  
Steel Component ◽  
Cross Sectional ◽  
Simply Supported ◽  
Simulation Based

The article deals with possibility of application of the simulation based reliability assessment SBRA Method in modeling of structures in the field of judgement of their serviceability. A steel simply supported beam of hollow circular cross sectional area was taken into account. Using rules of modeling it was modeled by the beam of the same shape, when its material was the composite material. Deflection of it was determined experimentally and using modeling rules the corresponding deflection of the steel beam was determined. Deflections of steel component and its composite model were determined using SBRA Method, realized when following random variable quantities as dimensions of bodies and corresponding geometric quantities, Young ́s modulus of elasticity E and loading force were taken into account.

scholarly journals Comparative Study of Structural Behaviour for Rolled and Castellated Steel Beams with Different Strengthening Techniques

2019 ◽  
Vol 5 (6) ◽  
pp. 1384-1394
Author(s):  
Shakir Mahmood Hadeed ◽  
Ahmad Jabbar Hussain Alshimmeri
Keyword(s):  
High Strength Concrete ◽  
Reference Beam ◽  
Construction Materials ◽  
High Strength ◽  
Steel Beams ◽  
Steel Beam ◽  
Structural Behaviour ◽  
Element Analysis ◽  
Strength Concrete ◽  
Structural Applications

Currently, the castellated steel beams are used widely because of their useful structural applications and serviceable performance due to their good significant properties such as light weight, facility in construction, materials economize and strength. The castellated steel beam fabricated from its origin solid beam (I-beam) by cutting its web in a zigzag path and then re-joined the two halve by welding so the height of the castellated beam expanded about 50%. The aim of this paper is to study the effect of castellation with and without strengthening on the structural behaviour of castellated beams and compare the results with the origin solid steel beam. Three castellated beams with deferent configuration in addition to solid beam subjected to two equal point loads at mid third of span with simple support condition were analysed numerically using finite element analysis by Abaqus software virgin (6.14.5) .The results show that the load carrying capacity values of castellated steel beams that represent (second, third& fourth) models were increased by (39.11,105.95&124.77) % respectively compared with origin solid beam  due to increase beams stiffness after castellation and strengthening process, while mid-span deflection values at service load were decreased by (36.36,9.10&27.27) % respectively comparing with the origin solid steel beam due to increasing section dimensions and stiffness after castellation process and using strengthening technique respectively. Also it was seen that the maximum ultimate moment and ductility were observed in the fourth model that strengthened by high strength concrete and lacing reinforcement so they increased by 124.79% and 165.65% respectively as compare to reference beam, while the third model that strengthened by high strength concrete was stiffer than other beams.

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